The use of a permeable facing fabric or film on an acoustical absorber to improve its low frequency response has been shown in the literature and in numerous commercial applications, primarily in the building and construction field. Recently this concept has been applied to motor vehicle interior acoustical products. While these arrangements may demonstrate improved sound transmission loss in the mid-frequency range as compared to a double-walled system, they also typically exhibit decreased sound transmission loss at higher frequencies. Furthermore, a porous surface may cause several practical problems. When used on the floor of a motor vehicle, an acoustical absorber having a water-permeable facing is susceptible to water intrusion which may cause formation of mildew and odor in the underpad, as well as rust the floor pan in some cases.